It's a rare thing in this industry to be potentially on the verge of a paradigm shift, as a stream of consistent, impressive, but nonetheless incremental upgrades to a given technology runs out of road and is overtaken by an entirely new way of doing things. Such will one day be the case with electric and hybrid motors supplanting internal combustion engines in cars. Maybe. Right after they start to fly.

Some would argue that we're on the brink of a dramatic shift in the storage world. Mechanical hard drives that store data on platters spinning at thousands of revolutions per minute have reigned here for decades, and today's finest are technical marvels of microscopic mechanics. But can they stand up to flash-based solid-state drives riding the tidal wave that is Moore's Law?

Solid-state drives have recently become more prominent on the mobile front, where their low power consumption and robust shock tolerance are clear advantages over the mechanical monarchy. Densities are up and prices are falling, too, allowing for budget models that won't have you pondering auctioning off a kidney. The latest mechanical mobile drives are hardly dinosaurs, though. Perpendicular recording has done wonders, enabling the latest 2.5" disks to spin an impressive 320GB at 7,200 RPM, with 16MB of cache riding shotgun—that was a well-equipped 3.5" desktop drive a couple of years ago.

The obvious questions, then, are how these two competing storage technologies stack up and which is right for you. In search of answers, we've rounded up seven 2.5" mobile drives, including SSDs from OCZ, Samsung, and Super Talent, and traditional mechanical drives from Seagate and Western Digital. Read on for the enlightening results of this battle between machines and memory.